Scattered light reduction in Sagnac Speed Meters with Tunable Coherence
Abstract
Sagnac Speed Meter and ring resonators can be used as high precision instruments, but they are limited in their sensitivity through scattered light causing non-linear noise. Here, we experimentally demonstrate a technique called Tunable Coherence, where the long coherence length of the laser is broken in a controlled way, to suppress the coupling of scattered light in a Sagnac interferometer. We demonstrate a scattered light suppression of 24.2 dB in a Sagnac interferometer and discuss the experimental limitations. Further, we show an analytical discussion on how Tunable Coherence could be a fundamental solution to light scattering back from optical surfaces into the counter propagating beam, which is an issue particularly in ring resonators.
Keywords
Cite
@article{arxiv.2502.07383,
title = {Scattered light reduction in Sagnac Speed Meters with Tunable Coherence},
author = {Leonie Eggers and Daniel Voigt and Oliver Gerberding},
journal= {arXiv preprint arXiv:2502.07383},
year = {2026}
}